Technical Field
The present invention relates to a technique for using a peripheral device in an information processing apparatus, such as an image forming apparatus.
Description of the Related Art
Image forming apparatuses having various functions such as copy, scan, and fax are widespread. Such image forming apparatuses maybe referred to as “multi function peripherals (MFPs)”.
Late models of image forming apparatuses have come to additionally provide with such functions as a web browser, a web server, or optical character recognition (OCR).
The foregoing various functions are very often managed integrally by a single system (e.g., an operating system).
A plurality of systems may nonetheless be disposed in a single housing and the foregoing various functions maybe managed by different systems.
One possible configuration may include an MFP unit having a first operating system and a server unit having a second operating system. The MFP unit achieves the copy, scan, and fax functions, while the server unit achieves the web browser, web server, and OCR functions. This single housing may include one display that is shared between the MFP unit and the server unit.
Even later models of image forming apparatuses are equipped with an interface, such as a universal serial bus (USB), for connecting peripheral devices.
Even when attempts are made by a plurality of the foregoing functions to use a peripheral device, integral management of the functions by a single system substantially eliminates contention of access to a peripheral device by a plurality of functions.
Contention of access to a peripheral device is, however, highly likely to occur when the foregoing functions are managed by different systems.
Well-known techniques of sharing a single peripheral device among a plurality of apparatuses may be applied to the image forming apparatus. The following techniques are known to date.
JP 2008-271215 A discloses a USB hub as described below. Specifically, the USB hub includes an exclusive control unit disposed between USB host controllers and USB peripheral controllers. The USB peripheral controllers are cyclically granted a temporary right of use at any unit time interval. The USB hub is configured such that, when a communication is received from a first PC connected with a USB peripheral controller that has acquired the temporary right of use, the right of use is granted to a USB host controller connected with a first USB device with which the first PC communicates and the USB peripheral controller connected with the first PC. The USB hub is further configured such that a NAK response is sent to any communication with the first USB device from any PC other than the first PC.
JP 2011-134096 A discloses an image forming apparatus as describe below. The image forming apparatus is capable of communicating with an information processing apparatus and an operating unit through a USB interface. The image forming apparatus includes a changeover unit that changes a connection state of a USB device and a USB host via the USB interface. When it is determined that the image forming apparatus can communicate with the information processing apparatus through the USB interface and the information processing apparatus can control the operating unit, the changeover unit changes from a first connection state in which the image forming apparatus as a USB host is connected with the operating unit as a USB device to a second connection state in which the information processing apparatus as a USB host is connected with the operating unit as a USB device.
JP 2005-339146 A discloses an image forming apparatus as describe below. The image forming apparatus includes a connection changeover circuit. The connection changeover circuit connects, in advance, a downstream port with a USB host circuit over a USB connection line. DPS discovery is executed when a DSC that supports PictBridge is connected to the downstream port. When the DPS discovery is successful, the connection state between the DSC and the USB host circuit is maintained. In contrast, when a scanner that does not support PictBridge is connected and DPS discovery fails, the USB connection line is disconnected. After a lapse of a predetermined period of time, the USB connection line is connected and the scanner is connected with a USB hub circuit, and the scanner is thereby allowed to be recognized by a PC.
The known technique described above allows a single peripheral device to be shared among a plurality of systems (e.g., PCs) through performance of exclusive control.
A need nonetheless exists in an image forming apparatus including a plurality of systems, such as an MFP unit and a server unit, housed in a single housing for making peripheral devices easier to use for users than before.